Page 91 - Oil and Gas Production Handbook An Introduction to Oil and Gas Production

about 2000 liters (500 Gallons) of
antifoam could be used. At a cost of
2 € a liter, 10 $ a gallon in bulk,
antifoam alone will cost some 4000
€ or 5000 USD per day.

The most common chemicals and
their uses are:

Scale inhibitor The well flow
contains
several
different
contaminants such as salts, chalk, and traces of
radioactive materials. As pressure and temperature
changes, these may precipitate and deposit in pipes,
heat exchangers, valves and tanks. As a result these
may clog up or become stuck. The scale inhibitor will
prevent the contaminants from separating out. Scale
or sediment inhibitor is applied to wellheads and
production equipment.
Emulsion breaker Water and oil cannot mix to form a solution. However
small drops of oil will disperse in water and small
water drops will disperse in oil. These drops are held
suspended by plus and minus electrostatic forces at
the molecular level. This is called an emulsion and will
form a layer between the oil and water. Although the
emulsion layer will eventually break down naturally, it
takes time, too much time. An emulsion breaker is
added to prevent formation, and breakdown of the
emulsion layer by causing the droplets to merge and
grow. Sand and particles will normally be carried out
by the water and be extracted in water treatment.
However, the emulsion can trap these particles and
sink to the bottom as a sticky sludge that is difficult to
remove during operation.
Antifoam The sloshing motion inside a separator will cause
foaming. This foam will cover the fluid surface and
prevent gas from escaping. Foam also reduces the
gas space inside the separator, and can pass the
demister and escape to the gas outlet in the form of
mist and liquid drops. An antifoam agent is introduced

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